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Fencer Intel
high 8.7

CVE-2026-59860 json

Kiota: XML Doc-Comment Newline Breakout Code Injection

published 4mo ago modified 18d ago also EUVD-2026-44931 , GHSA-3hrf-2gc2-mx32

cvss
8.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.3, Kiota is affected by a code-generation injection vulnerability in the C# XML documentation-comment sink (the description, externalDocs label, and externalDocs link fields emitted as /// … comments). When text from an OpenAPI description is written into single-line XML doc comments without stripping newline and Unicode line-terminator characters, an attacker can break out of the /// comment line and inject additional code into generated C# clients. This issue is fixed in version 1.29.1 and 1.32.3.

Patch / fix

  • nuget Microsoft.OpenApi.Kiota 1.29.1, 1.32.3
  • nuget Microsoft.OpenApi.Kiota.Builder 1.29.1, 1.32.3
  • microsoft kiota 1.29.1, 1.32.3
  • microsoft microsoft.openapi.kiota 1.29.1, 1.32.3
  • microsoft microsoft.openapi.kiota.builder 1.29.1, 1.32.3

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
3mo ago

Exploit prediction

1.38% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/microsoft/kiota/security/advisories/GHSA-3hrf-2gc2-mx32 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
nuget Microsoft.OpenApi.Kiota
>=1.30.0, <1.32.3
<1.29.1
1.32.3
1.29.1
nuget Microsoft.OpenApi.Kiota.Builder
>=1.30.0, <1.32.3
<1.29.1
1.32.3
1.29.1

Affected products

  • microsoft kiota

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of microsoft/kiota published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.